The present invention relates to a unit for delivering fuel from a fuel tank to the internal combustion engine of a motor vehicle.
More particularly, it relates to a unit of the above mentioned general type which has a feed pump arranged in a fuel tank and constructed as a flow pump with a substantially circular-cylindrical impeller rotating in a circular-cylindrical pump chamber.
Units of the above mentioned general type are known in the art. A feed unit is already known (DE-OS 35 09 374) in which this bore hole is arranged directly in the delivery duct and provided with a resilient valve flap which remains in its open position while gas is being conveyed, but when fuel is delivered is deformed against spring force by the more "viscous" medium and closes the opening of the bore hole on the duct side. However, such a construction requires a particularly costly assembly of the valve flap. There is also the risk that the open valve flap will scrape against the impeller of the feed pump when gas is conveyed causing unwanted noise and will finally be destroyed.